National Risk Index shapefile downloads use the value -9999 for data fields that contain or display
null values in other data formats. In addition, limitations of the shapefile file format cause minor differences 
in the display of a few large values between the same values stored in other available formats (e.g. Geodatabase and CSV).
Please consider this when you use the National Risk Index shapefile datasets.

For more information on null and other values in the National Risk Index data, see the 
National Risk Index Technical Documentation (available for download at: https://www.fema.gov/national-risk-index).